查看更多>>摘要：? 2022 Elsevier B.V.Transition metal phosphides (TMPs) have received widespread attention due to their high theoretical specific capacity and fast reaction kinetics. However, their poor conductivity and volume changes during the cycle limited their applications. Herein, we explore a facile and cost-effective way to prepare core–shell-like transition metal phosphides (TMPs: CoP, Ni2P, Cu3P) nanoparticles embedded into nitrogen doped porous carbon nanosheets (denoted as CoP@NDPCS, Ni2P@NDPCS, Cu3P@NDPCS) via biological material-driven assembly and self-template strategy. By self-assembled process, the amino and carbonyl groups in silk fibroin can chelate with metal ions, and then phytic acid added undergoes a coordination reaction with the metal components. Subsequently, core-shell TMPs nanoparticles supported by nitrogen doped porous carbon nanosheets were prepared by a one-step high-temperature calcination process. The obtained unique hybrid structure material with enough vacancy space to alleviate volume expansion exhibits ultra-high specific capacity and excellent cycling performance for the anode of lithium-ion batteries. The CoP@NDPCS, Ni2P@NDPCS and Cu3P@NDPCS electrodes exhibit the reversible capacities of 1014.2, 486.5 and 877 mAh g?1 at the current density of 500 mA g-1, respectively. The remarkable lithium storage performance of TMP@NDPCS indicates that a reasonable structure designed by biological material-driven is an effective and promising method to enhance the lithium storage of transition metal phosphides.
查看更多>>摘要：? 2022 Elsevier B.V.In accidental scenarios of high temperature gas-cooled reactors, both oxidation of and irradiation to the SiC layer in tri-structural-isotropic (TRISO) fuel particles can change the microstructure and integrity of the fuel elements. In the present study, microstructure and defect evolution in the oxidized SiC layer of surrogate TRISO fuel particles under 1.2 MeV krypton ion irradiation was observed by in-situ transmission electron microscopy. The SiC layers oxidized in water vapor at 1200 °C were irradiated azt room temperature and 800 °C and at damage levels of 0.28–11.2 dpa, respectively. SiC and SiO2 were found to still be in their crystal structures at the damage level of 11.2 dpa at 800 °C, while SiC was observed to have been amorphized at only 0.56 dpa irradiation at room temperature. The defect number density at 800 °C was an order of magnitude lower than that in the sample irradiated at room temperature. Also, crystalline SiO2 had higher radiation resistance compared to SiC. A defect reaction rate theory was utilized to understand the fundamental defect evolution process and irradiation resistance difference.
查看更多>>摘要：? 2022 Elsevier B.V.Alloy 718 has been intensively investigated for additive manufacturing. While previous studies on additively manufactured alloy 718 typically have metallic phases only, in this work, we show that oxide nanoparticles can be introduced into alloy 718 via a reactive sintering mechanism. The introduction of micron scale Cr2O3 powder in alloy 718 powder led to the formation of a homogeneous distribution of Al and Ti rich oxide nanoparticles. This surprising finding arises from the chemical reaction between oxide powders and metal matrix containing Al and Ti. In comparison to the control alloy 718 without oxides, the presence of oxide nanoparticles dramatically alters the microstructure, leading to a relatively more equiaxed grain structure, while also reducing the residual stress. While the mechanical testing between the two material groups demonstrates comparable mechanical strength and tensile ductility at room temperature, the high-temperature (900 °C) mechanical properties of the oxide containing 718 samples were significantly improved over the control 718 samples. The apparent possibilities of using this reactive process to introduce oxide nanoparticles into metallic materials may have a general implication for the fabrication of oxide dispersion in various metal matrices via reactive additive manufacturing.
查看更多>>摘要：? 2022 Elsevier B.V.The aim of this study was to develop a ZrO2-Al2O3 composite coating with excellent mechanical, corrosion, and tribocorrosion behaviour on Zr-2.5 Nb alloy substrate for load-bearing implants. The bipolar waveforms utilizing cathodic duty cycles of 10, 20, and 40 were applied to produce composite coatings using the plasma electrolytic oxidation in an aluminate-phosphate electrolyte bath. The ZrO2-Al2O3 composite coatings had a net-like morphology with pores and cracks. When the cathodic duty cycle increased to 40, the Al2O3 was accumulated on the surface, with an enhanced thickness (5.39±0.67 μm) and compactness of the coating with significantly improved hardness (2x higher). The composite coating developed at the cathodic duty cycle of 40 displayed the highest corrosion performance in phosphate buffer saline (PBS) even after 16 weeks of immersion. Moreover, the tribocorrosion test indicated the lowest volume loss of about 0.038 mm3 and showed no potential fall-out during the sliding test against the SiC ball. In summary, the ZrO2-Al2O3 composite coating developed by the PEO process resulted in noticeable corrosion and tribocorrosion performance of the Zr-2.5 Nb alloy desirable for knee implants.
查看更多>>摘要：? 2022 Elsevier B.V.This work presents the study of new Ruddlesden-Popper phases, LaSrFe1- xCrxO4 (x = 0.0, 0.2, 0.4 and 0.6), synthesized by glycine-nitrate combustion method. In this research, we are for the first time reporting on a complete Ruddlesden-Popper series (n = 1) for the photocatalytic degradation of a dye. The effect of Cr3+ doping on the crystal structure, optical and magnetic properties of the LaSrFeO4 phase has also been systematically explored via different characterization techniques. Rietveld refinement of PXRD data indicates the formation of single phase compounds with tetragonal symmetry in the space group I4/mmm. The results show a decrease in the lattice parameters a and c, as well as the unit cell volume V, with increase in Cr3+ doping. The energy band gap (Eg) values calculated using the DRS spectra decreases with increase in Cr concentration. The magnetic measurements revealed dominant anti-ferromagnetic (AFM) interactions in all the phases and the appearance of weak ferromagnetic (FM) interactions with Cr3+ doping. The results are discussed by considering the increase in Fe3+─O─Cr3+ FM interaction in addition to the Fe3+─O─Fe3+ and Cr3+─O─Cr3+ AFM super-exchange interactions induced due to random distribution of Fe3+ and Cr3+ ions at the octahedral site. Rhodamine B, as a dye pollutant model, was used for evaluation of photocatalytic activity of the prepared phases. Enhanced photocatalytic activity was observed with the addition of Cr3+ substitution. The results show ~99 % degradation for x = 0.6 while only ~76 % degradation is shown for x = 0.0 sample in 40 min under visible light irradiation.
查看更多>>摘要：? 2022 Elsevier B.V.Porous carbon aerogels derived from abundant biomass, which possess a unique structure, a high specific surface area and heteroatom doping, are a promising electrodes material for supercapacitors (SCs). In this study, an innovative hierarchical porous material comprising cobalt decorated porous carbons derived from cellulose nanofiber / graphene / Zn/Co ZIF carbon aerogels (CRZCs) has been successfully synthesized by directional freeze drying and carbonization methods. Cellulose nanofibers (CNFs) and graphene (rGO) layers play not only a supporting role, but also an internal storage site for electrolytes, contributing to the diffusion of electrolytes to the surface of active substances, at the same time enhance hydrophilicity of the aerogel and contribute to uniformly disperse Zn/Co ZIF. What's more important is that the carbon aerogels possess hierarchical porous involving micropores, mesopores and macropores, which further aid electrolyte penetration and ion storage. Furthermore, benefiting from the synergetic effect of hierarchical porous, high surface area, high conductivity, the prepared CRZC electrode obtains a high specific capacitance (364.6 F g?1 at 1 A g?1), an extraordinary capacitance retention rate (83.4 % at 10 A g?1). Simultaneously, the assembled supercapacitor by CRZC 900 exhibits a high specific capacitance (121.4 F g?1 at 0.5 A g?1), good charging/discharging rates, and remarkable cycling stability (78.9 % capacitance retention over 10000 cycles). The energy density up to 18.9 Wh kg?1 is achieved at power density of 288.4 W kg?1, indicating its comprehensive applicability in energy storage. Finally, our results provide a general approach to construct hierarchical porous carbon aerogels for high-performance supercapacitors.
查看更多>>摘要：? 2022 Elsevier B.V.The quality of perovskite film seriously affects the performance of organic-inorganic hybrid halide perovskite solar cells. In this paper, we demonstrate an anti-solvent treatment by controlling the perovskite recrystallize to enhance the quality of perovskite film and photophysical properties, including crystallinity, high coverage and high absorption. The fabricated carbon-based perovskite solar cells show PCE improvement from 6.82% to 10.81% with less hysteresis, and remained 90% of the original value after 93 days in the air environment. Our work provides a way to prepare simple and stable perovskite devices with high stability and low cost.
查看更多>>摘要：? 2022 Elsevier B.V.The UV-enhanced sensing performance of the two-dimensional polyimide/indium oxide (2DPI/In2O3) based sensor towards NH3 was investigated at room temperature of 25 °C. The 2DPI/In2O3 composite materials with hydrogen bond were synthesized by hydrothermal method, which is sensitive to NH3 in the absence or presence of UV illumination. The microstructure, morphology and constituent elements of the prepared samples were characterized by SEM, TEM, XRD, XPS, FT-IR and UV–visible analysis. The as-prepared 2DPI/In2O3 based sensor shows the best sensing performance compared to those of pure 2DPI and pure In2O3 sensors. In terms of the sensitivity of the 2DPI/In2O3 based sensor, the synergistic effect between 2DPI and In2O3 leads to an enhancement of three times response of the composite sensors under UV illumination compared with the response of composite sensors without UV illumination. Particularly, the response time and recovery time of the 2DPI/In2O3 based sensor towards 1 ppm NH3 are shortened by 10 s and 20 s under 365 nm UV illumination, respectively. The significant enhancement in sensing performance is due to the formation of the heterojunction between 2DPI and In2O3. Besides, 2DPI acts as photocatalytic promoter in the 2DPI/In2O3 composite. The 2DPI/In2O3 based sensor is a promising candidate for UV-assisted NH3 detection at room temperature.
查看更多>>摘要：? 2022 Elsevier B.V.The isothermal section of the ytterbium-palladium-indium phase diagram was constructed at 600 °C in the Pd< 60 at% region, as a result of X-ray powder diffraction and scanning electron microscopy with energy dispersive X-ray analysis. The existence of a new ternary compound Yb5Pd2In was observed at this temperature, and its crystal structure was determined (structure type Mo5SiB2, space group I4/mcm, a = 0.78820(2) nm, c = 1.41596(5) nm). Magnetic and thermodynamic properties of two ternary compositions YbPdIn4 and Yb17Pd50In33 were also investigated. Yb17Pd50In33 presents a stable trivalent Yb3+, whereas in YbPdIn4 the Yb ion is in a nearly divalent state.
查看更多>>摘要：? 2022 Elsevier B.V.Chemical bath–deposited cadmium sulfide (CBD-CdS) is the most widely used buffer layer material for antimony selenosulfide (Sb2(S,Se)3) photovoltaic devices, but its medium band gap, large band gap offset with transparent conducting oxides, and surface defects must be addressed to improve its applicability. Hexagonal CdS films (60 nm thick) prepared using the thermal evaporation method were used as the buffer layers of Sb2(S,Se)3 photovoltaic devices. Compared with CBD-CdS (60 nm thick), thermal evaporation–deposited CdS (TED-CdS) films have a larger band gap and fewer surface defects. The Sb2(S,Se)3 film deposited on TED-CdS is more compact, and its 1D ribbons are stacked more vertically to the substrate. The band gap offset between CdS and fluorine-doped tin oxide glass decreases from 0.76 eV (CBD-CdS) to 0.60 eV (TED-CdS). Therefore, suppressed electron trap density and charge recombination, as well as improved light harvesting, are achieved. By replacing CBD-CdS with TED-CdS, the best device efficiency increases from 6.14 % to 7.16 %, with the open circuit voltage, short-circuit current density, and fill factor increasing from 0.660 V, 15.96 mA/cm2, and 58.37 % to 0.664 V, 17.39 mA/cm2, and 62.85 %, respectively. The device stability and reproducibility are also improved.
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